35mm. I'm using the vanilla 35mm carrier that came with the enlarger.

Har! As always, the answer to suffering is to look within.

I'm a little concerned about getting cut from the edges of the glass.
If I fold skotch tape around the edges of the glass, that would create
a slight gap between the sheets of glass that might not be a bad
thing: would it not solve the newton ring problem ?

On the other hand, I'm imagining some kind of plastic 3/4 square
plastic strip that I could pop around the edges of both sheets to hold
them together. Somewhere, for some purpose, there must be such a
thing.

And if I did end up w/Newton rings, I could just by a sheet of an
glass (http://www.fpointinc.com/web_store/Products/focal/fpnewt2.htm).

The dust problem is a fair trade for the negative popping issue.

Thanks. I think you just saved me $100 bucks!

Yes, enlargers with a right-angle lamphouse that employ a mirror to
reflect the light but not so much of the heat are superior.

Another posibility is a single sheet of anti-newton glass between the
negative and the light source. My Nikor neg carrier (similar to
Saunders) allows this. Since the neg normally bows upward it presses
against the glass. The top side of the glass is far enough out of the
plane of focus to greatly reduce the dust problem with a diffuse light
source.

Tim

I have the standard head.

This is an intriguing suggestion. The letering are no longer visible
on the bulb, but it looks just like the 75w bulb as for example in
this illustration: http://www.bhphotovideo.com/bnh/controller/home?O=productlist&A=details&Q=&sku=1
37121&is=REG.

Is it possible to get a stronger bulb that would have the same shape?

You may be on to something here. I am using the enlarger in a very,
very small closet. There's just barely enough room for me and the
enlarger, and I'm not a huge guy. (My wet space is in a bathroom and I
use a print drum.) So perhaps, indeed, the volume of air in that
closet is not sufficient to enable the head to dissipate the heat,
even from the normal 75W bulb. Does that sound plausible?

I never spend more than 10 minutes at a time in that closet to avoid
asphyxiating myself, but I'm starting to think that I ought to have
some kind of ventillation.

--Phil

It is also possible to make a carrier with glass on the top only, masonite
or mat board on the bottom, cut out of course to fit the negative. The
buckling is convex upward and thus is at least minimized by the glass on
top. This means only two surfaces to clean.

When I have had problems with Newton rings, it has been because of a speck
of something causing uneven contact with the glass, or a wet spot on the
neg. Waviness in the glass can also be a culprit.

If that is true, when builders use heat absorbing glass (HAG) for
home/buildings windows is just so we can see objects inside the
house/buildings the exact color they are?

When you don't have a HAG, the negative receives all the forms of radiation,
visible+IR and also plain heat that by convection/dissipation moves from the
bulb's hot filament to the condenser lenses and to the negative.  Adding a
HAG has probably 2 effects, firstly, it prevents a good portion of the IR to
reach the negative (less heat on the film) and secondly, adds another
"barrier" for the plain heat inside the condenser bulb chamber.  The IR
energy blocked by the HAG is not actually removed but converted into heat
(1st law of thermodynamics) which dissipates in the surroundings of the
filter (both sides unfortunately).  Now, there may be more
dissipation/transfer of heat on the side of the negative just because it is
the coolest side as supposed to the side where the actual source of energy
is (bulb).  Heat inside the chamber will eventually heat up all layers of
glass in between the bulb and the negative and by a combination of
convection/absorption/dissipation, a lot of the heat will get to the
negative.  We can say that the HAG reduces a little bit the heat (all sorts
of) on the negative, but mostly it just delays it, so the key is to have a
form of heat extraction (fan) in the condenser chamber, this way a lot of
the plain heat that the filament dissipates will be replaced by fresh air
from the environment, which in turn will cause the HAG to dissipate more of
the (IR blocked) heat on the condenser chamber.  The above is in part why My
Omega Chromega Dichroic enlarger puts less heat on the negative even with a
250watts lamp than my similar enlarger with condenser light source and just
75watts lamp.  The dichroic has a HAG right in front of the lamp and a fan
inside the lamp chamber.

Guillermo

That's not what the Beseler engineer told me. I'm entirely ready to
believe he is wrong, of course.

--Phil